For what it's worth, modern C# can evaluate top-level statements with no other ceremony. The following is a valid standalone C# program: Console.WriteLine("H

For what it's worth, modern C# can evaluate top-level statements with no other ceremony. The following is a valid standalone C# program: Console.WriteLine("Hello"); For REPLs, there are options like (my own) https://github.com/waf/CSharpRepl https://github.com/waf/CSharpRepl which stand on top of the Roslyn compiler infrastructure, which is quite extensive and can easily evaluate standalone functions and statements. It's still nowhere close to the REPLs of lisp and smalltalk, but it's a step in a more flexible direction.